Earlier quoted context omitted.
If you mean unions should become actual corporations that sell the service of organized labor to corporations that want it, I completely agree. If workers want to improve their bargaining position, they need to manage the business risks involved with things like workers getting sick themselves instead of relying on employers to do it. Then those risks can be managed in a way that is fair to workers, because they are…
I don't quite get how this is expected to work. Does this somehow avoid a management level of this proposed corporation who are going to be trying to maximize profits at the expense of the employees who are ostensibly in a worse bargaining position? At that point, the decision for the worker is only whether they're working directly for the end-exploiters or just the middle-exploiter.
The corporation that takes the union's role would be owned by the workers; that's the whole point. It would be more like a "worker's cooperative" from that point of view, the way unions as they currently exist are supposed to be, but it would be a corporation from the point of view of other corporations who wanted to hire organized labor, so it would be in a better bargaining position than unionized employees are today. The workers would come to a consensus as a cooperative on things like how the corporation would manage the business risk of unscheduled absences, and then the corporation owned by the workers would sell the service of organized labor to other corporations that wanted it, probably with various different service levels depending on things like how critical unscheduled absences would be, and with higher service levels costing more.